Lord MicroStrain G-Link-200, User Manual

Page: 28 / 70

G-Link
®
-200
User Manual
27
c. Derived Output Channels
There are four derived data channels available for the G- Link- 200. Using these data channels for
vibration analysis allows the ability to extend battery life while reducing data. Each operation is
performed on a window of data from the specified accelerometer axis. The timestamp associated with
each sweep is that of the last data point collected within that window. The derived data output rate must
be at least 32 times slower than the sample rate. (
See Derived Channel Variables on page 29 )
l
RMS is calculated by accumulating the mean squared of each chunk, dividing by the
number of chunks in the window, and taking the square root.
l
Crest Factor is calculated by taking the absolute maximum value from the window and
dividing by the RMS of the window.
l
Peak to Peak is calculated by subtracting the smallest value from the window from the
largest value.
l
IPS G-Link-200 Only
The RMS of the IPS is calculated by determining a cubic spline of a chunk, analytically integrating
the cubic spline, taking the RMS of the cubic spline integral, and multiplying by 386.2197 to convert
from Gs to in/sec
2
.